Camshaft assembly

ABSTRACT

A camshaft assembly for an internal combustion engine of a motor vehicle is disclosed. The camshaft assembly includes a camshaft extending along an axial direction and at least one cam non-rotatably arranged on the camshaft. An axial bearing is provided for at least one of an axial alignment and an axial fixing of the camshaft. The at least one cam is part of the axial bearing.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to German Application No. DE 10 2020 201 038.2 filed Jan. 29, 2020, the contents of which are hereby incorporated by reference in its entirety.

TECHNICAL FIELD

The present invention relates to a camshaft assembly, in particular for an internal combustion engine of a motor vehicle, and to an internal combustion engine having such a camshaft assembly.

BACKGROUND

In internal combustion engines of motor vehicles, rotatably mounted camshafts serve for adjusting inlet and exhaust valves of the combustion chamber provided in a respective cylinder block.

There, the said rotatable mounting of the camshaft in a fixed system—typically the said cylinder block of the internal combustion engine—proves to be problematic since technically involved and thus expensive to produce. Apart from this, the rotatable mounting with conventional camshafts requires relatively much installation space axially.

It is therefore an object of the present invention to show new ways in the rotatable mounting of camshafts of internal combustion engines. In particular, particularly cost-effective or/and space-saving solutions are to be found.

This object is solved through the subject of the independent patent claim(s). Preferred embodiments are subject of the dependent patent claims.

SUMMARY

Accordingly, the basic idea of the invention is to rotatably mount a camshaft by means of an axial bearing absorbing axial forces, wherein one of the cams arranged on the camshaft is part of such an axial bearing. Thus, a separate component in the axial bearing which—as part of the axial bearing—absorbs axial forces exerted on the axial bearing by the camshaft, can be dispensed with. With the solution introduced here the cam that is non-rotatably arranged on the camshaft in fact assumes this function. In this way, the mounting of the camshaft compared with conventional camshafts proves to be particularly simple. Apart from this, the installation space needed in the axial direction is reduced compared with conventional camshaft assemblies.

A camshaft assembly according to the invention, in particular for an internal combustion engine of a motor vehicle, comprises a camshaft extending along an axial direction, on which at least one cam is non-rotatably arranged. Furthermore, the camshaft assembly comprises an axial bearing for the axial alignment of the camshaft. “Axial alignment” here means that the axial bearing prevents an axial yielding of the camshaft, in particular in the cylinder head of an internal combustion engine. According to the invention, the cam arranged on the camshaft is part of the axial bearing. Thus, the cam additionally assumes the function of an axial bearing. The camshaft assembly of camshaft and axial bearing according to the invention is therefore technically constructed in a particularly simple manner in turn resulting in the desired cost advantages during the production of the camshaft assembly.

The camshaft assembly introduced here cannot only be employed for the valve control in internal combustion engines but also for driving a delivery device, for example a liquid pump, in particular a fuel or coolant pump. Also conceivable is the use for driving a sensor wheel.

According to a preferred embodiment, the axial bearing comprises a first and a second axial bearing element which are located opposite one another along the axial direction and between which a cam is arranged. The two bearing elements and the said cam are designed and matched to one another in such a manner that the camshaft with the cam can rotate relative to the bearing elements about a centre longitudinal axis of the camshaft extending along the axial direction.

Particularly preferably, the cam is clamped in between the two bearing elements so as to be rotatably adjustable about the centre longitudinal axis of the camshaft.

According to another preferred embodiment, the axial bearing comprises a first and a second cam which are arranged spaced apart from one another and non-rotatably on the camshaft. Furthermore, the axial bearing comprises a first and a second axial bearing element. Preferably, the two bearing elements are arranged spaced apart from one another along the axial direction. The two cams and the two bearing elements in this embodiment are arranged relative to one another on or at the camshaft in such a manner that the first bearing element and the first cam limit an axial movement of the camshaft in the axial direction and the second bearing element and the second cam limit an axial movement of the camshaft opposite to the axial direction.

Particularly preferably, the two bearing elements are arranged between the two cams along the axial direction.

Alternatively to this and likewise particularly preferably, the two cams can be arranged between the two bearing elements along the axial direction.

According to a further advantageous further development, the two axial end faces of the at least one cam facing the bearing elements and the two axial end faces of the two bearing elements facing the at least one cam each form sliding surfaces of the axial bearing.

Particularly preferably, the bearing elements are designed for absorbing axial forces. In this way, the desired axial guidance of the camshaft is ensured without accompanying damage to or even destruction of the bearing elements in particular in a long-term operation of the assembly in a motor vehicle.

According to another advantageous further development, the two bearing elements can each be designed as bearing sleeve with a through-opening, through which the camshaft engages. In this way, the camshaft can be rotatably mounted with little radial play. Preferably, the two bearing sleeves, in the mounted state, completely surround the cam, with the exception of the two through-openings.

Particularly preferably, the two bearing elements or bearing sleeves can be formed as identical parts. The use of identical parts produces further cost advantages in the production of the camshaft assembly.

According to a preferred embodiment, the axial bearing consists of the cam and the two bearing elements. This embodiment is a particularly simple design construction and thus cost-effective in the production.

Apart from this, the invention relates to an internal combustion engine, in particular for a motor vehicle. The internal combustion engine comprises at least one cylinder block, preferentially two or more cylinder blocks, which (in each case) comprise(s) a combustion chamber and at least one adjustable valve for introducing fresh air into the combustion chamber or for discharging exhaust gas out of the combustion chamber. Furthermore, the internal combustion engine comprises a camshaft assembly according to the invention explained above. The advantages of the camshaft assembly according to the invention explained above therefore apply also to the internal combustion engine according to the invention. Here, the two bearing elements of the axial bearing of the camshaft assembly are arranged fixed in place relative to the (respective) cylinder block. In the internal combustion engine according to the invention, the cam of the axial bearing of the camshaft assembly is drive-connected to the valve in order to adjust the same.

According to a preferred embodiment of the internal combustion engine, the camshaft is rotatably mounted on the (respective) cylinder block by means of at least one radial bearing. Combined with the axial bearing, the desired rotatability of the camshaft relative to the cylinder block combined with the likewise desired axial guidance or fixing materialises.

Further important features and advantages of the invention are obtained from the subclaims, from the drawings and from the associated figure description by way of the drawings.

It is to be understood that the features mentioned above and still to be explained in the following cannot only be used in the respective combination stated but also in other combinations or by themselves without leaving the scope of the present invention.

Preferred exemplary embodiments of the invention are shown in the drawings and are explained in more detail in the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

It shows, in each case schematically:

FIG. 1 an example of an assembly according to the invention,

FIG. 2 a version of the example of FIG. 1.

DETAILED DESCRIPTION

The FIG. 1 illustrates an example of a camshaft assembly 1 according to the invention for an internal combustion engine of a motor vehicle. The camshaft assembly 1 comprises a camshaft 2 extending along an axial direction A. On the camshaft 2, multiple cams 3 are arranged non-rotatably and spaced apart from one another along the axial direction A. Here, the axial direction A extends along a centre longitudinal axis M of the camshaft 2. A radial direction R extends orthogonally to the axial direction away from the centre longitudinal axis M. A circumferential direction U circulates, perpendicularly both to the axial direction A and also to the radial direction R, about the centre longitudinal axis M.

Furthermore, the camshaft assembly 1 comprises an axial bearing 4 for aligning or fixing the camshaft 2 along the axial direction A. One of the cams 3—which in the following is referred to with the reference number 3 a—is part of this axial bearing 4. In addition to the cam 3 a, the axial bearing 4 comprises a first and a second axial bearing element 5 a, 5 b. The two bearing elements 5 a, 5 b are formed as parts of the axial bearing 4 for absorbing axial forces exerted by the cam 3 a. To this end, the two bearing elements 5 a, 5 b are arranged spaced apart from one another along the axial direction A and lie opposite one another along the axial direction A. The cam 3 a co-forming the axial bearing 4 is arranged along the axial direction A and between the two bearing elements 5 a, 5 b, namely in such a manner that the camshaft 2 with the cam 3 a can rotate relative to the two bearing elements 5 a, 5 b along the circumferential direction U about the centre longitudinal axis M of the camshaft 2. To this end, the cam 3 a is clamped in between the two bearing elements 5 a, 5 b so as to be rotatably adjustable along the circumferential direction U. In the example scenario, the axial bearing 4 consists of the cam 3 a and the two bearing elements 5 a, 5 b, i.e. the axial bearing 4 is formed in three parts.

The two axial end faces 8 of the cam 3 a facing the bearing elements 5 a, 5 b and the two axial end faces 9 of the two bearing elements 5 a, 5 b facing the cam 3 a each form sliding surfaces of the axial bearing 4. The two bearing elements 5 a, 5 b can each be formed as bearing sleeve 6 a, 6 b with a through-opening 7 a and 7 b respectively, through which the camshaft 2 engages as illustrated in FIG. 1. Practically, the two bearing elements 5 a, 5 b and bearing sleeves 6 a, 6 b respectively can be formed as identical parts.

Practically, one or more of the said sliding surfaces can be provided with a protective coating (not shown), which can in particular have a wear-reducing effect.

The camshaft assembly 1 of FIG. 1 can be used for example in an internal combustion engine (not shown) for a motor vehicle. This internal combustion engine comprises one, two or more cylinder blocks, in each of which a combustion chamber and adjustable valves for introducing fresh air into the combustion chamber and for discharging exhaust gas out of the combustion chamber are provided. Furthermore, the internal combustion engine comprises the camshaft assembly 1 explained above. Here, the two bearing elements 5 a, 5 b of the axial bearing 4 are preferably arranged fixed in place relative to the respective cylinder block. In this way, the camshaft 2 is axially guided relative to the cylinder block of the internal combustion engine by means of the two bearing elements 5 a, 5 b. Here, the cam 3 a of the axial bearing is drive-connected to one of the adjustable valves.

The further cams 3 non-rotatably arranged on the camshaft 2, which in contrast with the cam 3 a are not part of the axial bearing 4, can be drive-connected to the remaining valves of the internal combustion engine. The rotatable mounting of the camshaft 2 with the cams 3 on the cylinder block can be realised by means of at least one radial bearing (not shown).

FIG. 2 illustrates a version of the example of FIG. 1. Just as in the example of FIG. 1, the assembly 1 according to FIG. 2 also comprises two bearing elements 5 a, 5 b which are arranged spaced apart from one another along the axial direction A. The example of FIG. 2 differs from the example of FIG. 1 in that the axial bearing 4 comprises two cams 3 a, 3 b, which, spaced apart from one another along the axial direction A, are non-rotatably arranged on the camshaft 2. The two cams 3 a, 3 b and the two bearing elements 5 a, 5 b of the axial bearing 4 are arranged axially relative to one another on or at the camshaft 2 in such a manner that the first bearing element 5 a and the first cam 3 a limit an axial movement of the camshaft 2 in the axial direction A and the second bearing element 5 b and the second cam 3 b limit an axial movement of the camshaft 2 opposite to the axial direction A. In this way, the desired axial guidance of the camshaft 2 in the axial direction A and opposite to the axial direction A can be realised analogously to the example of FIG. 1. To this end, the two bearing elements 5 a, 5 b can be arranged between the two cams 3 a, 3 b along the axial direction A as shown in FIG. 2. Alternatively to this it is also conceivable however that the two cams 3 a, 3 b are arranged between the two bearing elements 5 a, 5 b along the axial direction A (not shown in FIG. 2). 

1. A camshaft assembly, comprising: a camshaft extending along an axial direction and at least one cam non-rotatably arranged on the camshaft, an axial bearing for at least one of an axial alignment and an axial fixing of the camshaft, wherein the at least one cam is part of the axial bearing.
 2. The assembly according to claim 1, wherein the axial bearing includes a first axial bearing element and a second axial bearing element that lie opposite one another along the axial direction, and wherein the at least one cam is arranged axially between the first axial bearing element and the second axial bearing element so that the camshaft with the at least one cam can rotate relative to the first bearing element and the second bearing element about a centre longitudinal axis of the camshaft running in the axial direction.
 3. The assembly according to claim 2, wherein the at least one cam is clamped between the first bearing element and the second bearing element so as to be rotatably adjustable about the centre longitudinal axis of the camshaft.
 4. The assembly according to claim 1, wherein the axial bearing includes a first cam and a second cam non-rotatably arranged on the camshaft spaced apart from one another, and a first axial bearing element and a second axial bearing element arranged relative to one another on or at the camshaft such that the first bearing element and the first cam limit a movement of the camshaft in the axial direction and the second bearing element and the second cam limit an axial movement of the camshaft against the axial direction.
 5. The assembly according to claim 4, wherein the first bearing element and the second bearing element are arranged between the first cam and the second cam along the axial direction.
 6. The assembly according to claim 4, wherein the first cam and the second cam are arranged between the first bearing element and the second bearing element along the axial direction.
 7. The assembly according to claim 2, wherein two axial end faces of the at least one cam facing the first bearing element and the second bearing element and two end faces of the first bearing element and the second bearing element facing the at least one cam each form sliding surfaces of the axial bearing.
 8. The assembly according to claim 2, wherein the first bearing element and the second bearing element are structured for absorbing axial forces.
 9. The assembly according to claim 2, wherein the axial bearing consists of the at least one cam and the first bearing element and the second bearing element.
 10. An internal combustion engine, comprising: at least one cylinder block that comprises a combustion chamber and at least one adjustable valve for introducing fresh air into the combustion chamber or for discharging exhaust gas out of the combustion chamber, a camshaft assembly, the camshaft assembly including: a camshaft extending along an axial direction and at least one cam non-rotatably arranged on the camshaft, an axial bearing for at least one of an axial alignment and an axial fixing of the camshaft, wherein the at least one cam is part of the axial bearing, wherein the axial bearing includes a first axial bearing element and a second axial bearing element that lie opposite one another along the axial direction, and wherein the at least one cam is arranged axially between the first axial bearing element and the second axial bearing element such that the camshaft with the at least one cam can rotate relative to the first axial bearing element and the second axial bearing element about a centre longitudinal axis of the camshaft running in the axial direction, wherein the first bearing element and the second bearing element are arranged fixed in place relative to the at least one cylinder block, and wherein the at least one cam of the axial bearing is drive-connected to the at least one valve for adjusting the at least one valve.
 11. The internal combustion engine according to claim 10, wherein the camshaft is rotatably mounted on the at least one cylinder block via a radial bearing.
 12. The internal combustion engine according to claim 10, wherein the at least one cam is clamped between the first axial bearing element and the second axial bearing element so as to be rotatably adjustable about the centre longitudinal axis of the camshaft.
 13. The internal combustion engine according to claim 10, wherein the axial bearing further includes a first cam and a second cam non-rotatably arranged on the camshaft spaced apart from one another, and wherein the first cam and the first bearing element are structured and arranged to limit a first axial movement of the camshaft in the axial direction, and the second cam and the second bearing element are structured and arranged to limit a second axial movement of the camshaft against the axial direction.
 14. The internal combustion engine according to claim 13, wherein the first bearing element and the second bearing element are arranged between the first cam and the second cam along the axial direction.
 15. The internal combustion engine according to claim 13, wherein the first cam and the second cam are arranged between the first bearing element and the second bearing element along the axial direction.
 16. The internal combustion engine according to claim 13, wherein two axial end faces of the at least one cam that face the first bearing element and the second bearing element and two end faces of the first bearing element and the second bearing element that face the at least one cam form sliding surfaces of the axial bearing.
 17. The internal combustion engine according to claim 13, wherein the first bearing element and the second bearing element are structured for absorbing axial forces.
 18. The internal combustion engine according to claim 10, wherein the axial bearing consists of the at least one cam and the first bearing element and the second bearing element.
 19. The internal combustion engine according to claim 10, wherein two axial end faces of the at least one cam that face the first bearing element and the second bearing element and two end faces of the first bearing element and the second bearing element that face the at least one cam form sliding surfaces of the axial bearing.
 20. The internal combustion engine according to claim 10, wherein the first bearing element and the second bearing element are structured for absorbing axial forces. 